2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
6 * This handles basic git sha1 object files - packing, unpacking,
13 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
14 #define O_NOATIME 01000000
20 static unsigned int sha1_file_open_flag = O_NOATIME;
22 static unsigned hexval(char c)
24 if (c >= '0' && c <= '9')
26 if (c >= 'a' && c <= 'f')
28 if (c >= 'A' && c <= 'F')
33 int get_sha1_hex(const char *hex, unsigned char *sha1)
36 for (i = 0; i < 20; i++) {
37 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
46 int get_sha1_file(const char *path, unsigned char *result)
49 int fd = open(path, O_RDONLY);
54 len = read(fd, buffer, sizeof(buffer));
58 return get_sha1_hex(buffer, result);
61 int get_sha1(const char *str, unsigned char *sha1)
63 static char pathname[PATH_MAX];
64 static const char *prefix[] = {
75 if (!get_sha1_hex(str, sha1))
79 for (p = prefix; *p; p++) {
80 snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str);
81 if (!get_sha1_file(pathname, sha1))
88 char * sha1_to_hex(const unsigned char *sha1)
90 static char buffer[50];
91 static const char hex[] = "0123456789abcdef";
95 for (i = 0; i < 20; i++) {
96 unsigned int val = *sha1++;
97 *buf++ = hex[val >> 4];
98 *buf++ = hex[val & 0xf];
103 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
106 for (i = 0; i < 20; i++) {
107 static char hex[] = "0123456789abcdef";
108 unsigned int val = sha1[i];
109 char *pos = pathbuf + i*2 + (i > 0);
110 *pos++ = hex[val >> 4];
111 *pos = hex[val & 0xf];
116 * NOTE! This returns a statically allocated buffer, so you have to be
117 * careful about using it. Do a "strdup()" if you need to save the
120 * Also note that this returns the location for creating. Reading
121 * SHA1 file can happen from any alternate directory listed in the
122 * SHA1_FILE_DIRECTORIES environment variable if it is not found in
123 * the primary object database.
125 char *sha1_file_name(const unsigned char *sha1)
127 static char *name, *base;
130 char *sha1_file_directory = get_object_directory();
131 int len = strlen(sha1_file_directory);
132 base = xmalloc(len + 60);
133 memcpy(base, sha1_file_directory, len);
134 memset(base+len, 0, 60);
137 name = base + len + 1;
139 fill_sha1_path(name, sha1);
143 static struct alternate_object_database
149 static void prepare_alt_odb(void)
153 const char *cp, *last;
155 const char *alt = getenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
157 for (totlen = pass = 0; pass < 2; pass++) {
161 cp = strchr(last, ':') ? : last + strlen(last);
163 /* 43 = 40-byte + 2 '/' + terminating NUL */
164 int pfxlen = cp - last;
165 int entlen = pfxlen + 43;
169 alt_odb[i].base = op;
170 alt_odb[i].name = op + pfxlen + 1;
171 memcpy(op, last, pfxlen);
172 op[pfxlen] = op[pfxlen + 3] = '/';
178 while (*cp && *cp == ':')
184 alt_odb = buf = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
185 alt_odb[i].base = alt_odb[i].name = 0;
186 op = (char*)(&alt_odb[i+1]);
190 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
193 char *name = sha1_file_name(sha1);
199 for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
200 fill_sha1_path(name, sha1);
201 if (!stat(alt_odb[i].base, st))
202 return alt_odb[i].base;
207 int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
210 unsigned char real_sha1[20];
214 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
215 SHA1_Update(&c, map, size);
216 SHA1_Final(real_sha1, &c);
217 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
220 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
225 char *filename = find_sha1_file(sha1, &st);
228 error("cannot map sha1 file %s", sha1_to_hex(sha1));
232 fd = open(filename, O_RDONLY | sha1_file_open_flag);
234 /* See if it works without O_NOATIME */
235 switch (sha1_file_open_flag) {
237 fd = open(filename, O_RDONLY);
246 /* If it failed once, it will probably fail again. Stop using O_NOATIME */
247 sha1_file_open_flag = 0;
249 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
251 if (-1 == (int)(long)map)
257 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
264 /* Get the data stream */
265 memset(&stream, 0, sizeof(stream));
266 stream.next_in = map;
267 stream.avail_in = mapsize;
268 stream.next_out = buffer;
269 stream.avail_out = sizeof(buffer);
271 inflateInit(&stream);
272 ret = inflate(&stream, 0);
275 if (sscanf(buffer, "%10s %lu", type, size) != 2)
278 bytes = strlen(buffer) + 1;
279 buf = xmalloc(*size);
281 memcpy(buf, buffer + bytes, stream.total_out - bytes);
282 bytes = stream.total_out - bytes;
283 if (bytes < *size && ret == Z_OK) {
284 stream.next_out = buf + bytes;
285 stream.avail_out = *size - bytes;
286 while (inflate(&stream, Z_FINISH) == Z_OK)
293 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
295 unsigned long mapsize;
298 map = map_sha1_file(sha1, &mapsize);
300 buf = unpack_sha1_file(map, mapsize, type, size);
301 munmap(map, mapsize);
307 void *read_object_with_reference(const unsigned char *sha1,
308 const unsigned char *required_type,
310 unsigned char *actual_sha1_return)
315 unsigned char actual_sha1[20];
317 memcpy(actual_sha1, sha1, 20);
320 const char *ref_type = NULL;
322 buffer = read_sha1_file(actual_sha1, type, &isize);
325 if (!strcmp(type, required_type)) {
327 if (actual_sha1_return)
328 memcpy(actual_sha1_return, actual_sha1, 20);
331 /* Handle references */
332 else if (!strcmp(type, "commit"))
334 else if (!strcmp(type, "tag"))
335 ref_type = "object ";
340 ref_length = strlen(ref_type);
342 if (memcmp(buffer, ref_type, ref_length) ||
343 get_sha1_hex(buffer + ref_length, actual_sha1)) {
347 /* Now we have the ID of the referred-to object in
348 * actual_sha1. Check again. */
352 int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1)
357 unsigned char sha1[20];
360 static char tmpfile[PATH_MAX];
364 /* Generate the header */
365 hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
369 SHA1_Update(&c, hdr, hdrlen);
370 SHA1_Update(&c, buf, len);
371 SHA1_Final(sha1, &c);
374 memcpy(returnsha1, sha1, 20);
376 filename = sha1_file_name(sha1);
377 fd = open(filename, O_RDONLY);
380 * FIXME!!! We might do collision checking here, but we'd
381 * need to uncompress the old file and check it. Later.
387 if (errno != ENOENT) {
388 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
392 snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
394 fd = mkstemp(tmpfile);
396 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
401 memset(&stream, 0, sizeof(stream));
402 deflateInit(&stream, Z_BEST_COMPRESSION);
403 size = deflateBound(&stream, len+hdrlen);
404 compressed = xmalloc(size);
407 stream.next_out = compressed;
408 stream.avail_out = size;
411 stream.next_in = hdr;
412 stream.avail_in = hdrlen;
413 while (deflate(&stream, 0) == Z_OK)
416 /* Then the data itself.. */
417 stream.next_in = buf;
418 stream.avail_in = len;
419 while (deflate(&stream, Z_FINISH) == Z_OK)
422 size = stream.total_out;
424 if (write(fd, compressed, size) != size)
425 die("unable to write file");
429 ret = link(tmpfile, filename);
434 * Coda hack - coda doesn't like cross-directory links,
435 * so we fall back to a rename, which will mean that it
436 * won't be able to check collisions, but that's not a
439 * When this succeeds, we just return 0. We have nothing
442 if (ret == EXDEV && !rename(tmpfile, filename))
448 fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
451 /* FIXME!!! Collision check here ? */
457 int write_sha1_from_fd(const unsigned char *sha1, int fd)
459 char *filename = sha1_file_name(sha1);
463 unsigned char real_sha1[20];
469 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
472 return error("Couldn't open %s\n", filename);
474 memset(&stream, 0, sizeof(stream));
476 inflateInit(&stream);
482 size = read(fd, buf, 4096);
487 return error("Connection closed?");
488 perror("Reading from connection");
491 write(local, buf, size);
492 stream.avail_in = size;
493 stream.next_in = buf;
495 stream.next_out = discard;
496 stream.avail_out = sizeof(discard);
497 ret = inflate(&stream, Z_SYNC_FLUSH);
498 SHA1_Update(&c, discard, sizeof(discard) -
500 } while (stream.avail_in && ret == Z_OK);
502 } while (ret == Z_OK);
506 SHA1_Final(real_sha1, &c);
507 if (ret != Z_STREAM_END) {
509 return error("File %s corrupted", sha1_to_hex(sha1));
511 if (memcmp(sha1, real_sha1, 20)) {
513 return error("File %s has bad hash\n", sha1_to_hex(sha1));
519 int has_sha1_file(const unsigned char *sha1)
522 return !!find_sha1_file(sha1, &st);
525 int index_fd(unsigned char *sha1, int fd, struct stat *st)
527 unsigned long size = st->st_size;
533 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
535 if ((int)(long)buf == -1)
538 ret = write_sha1_file(buf, size, "blob", sha1);